1. Field of the Invention
The present invention relates to a head slider accommodated in a recording medium drive such as a hard disk drive (HDD), in particular, to a flying head slider comprising a slider body, a generally flat bottom surface defined on the slider body, a front rail standing on the bottom surface at an upstream or windward position, and an air bearing surface defined on the front rail.
2. Description of the Prior Art
A load/unload mechanism employing a ramp is well known in the technical field of a magnetic disk drive such as a hard disk drive (HDD). The ramp is designed to support an elastic head suspension, carrying a head slider at the tip end, when a magnetic recording disk stands still. For example, the ramp serves to cause bending of the head suspension, in response to an outward movement of the head slider in the radial direction of the magnetic recording disk, so as to keep the head slider distanced from the surface of the magnetic recording disk. Without the support of the ramp, the head slider cannot keep distanced from the surface of the magnetic recording disk when the magnetic recording disk stands still.
When the head suspension is released from the support of the ramp in response to an inward movement of the head slider, the head slider is forced to contact the surface of the magnetic recording disk. In this case, the head slider cannot keep distanced from the surface of the magnetic recording disk without a lift resulting from an airflow generated along the surface of the rotating magnetic recording disk. If the head slider takes an inclined attitude different from a predetermined normal or horizontal attitude, the head slider cannot receive a lift enough to fly above the surface of the magnetic recording disk. The elasticity of the head suspension causes the head slider to collide against the surface of the magnetic recording disk. In particular, the head slider including a front rail extending in the lateral direction of a slider body is designed to allow generation of a larger negative pressure behind the front rail, so that the head slider tends to suffer from the collision with the assistance of the negative pressure in the aforementioned situation.
The head slider can be formed to receive a relatively larger lift even when the head slider takes the inclined attitude. This enables a reliable prevention of the collision of the head slider against the magnetic recording disk when the head suspension is released from the support of the ramp. However, in this case, the behavior of the head slider becomes sensitive to variation in the flow rate of the airflow. For example, the stability is lost in the attitude of the head slider. Specifically, the pitch angle of the head slider tends to remarkably increase as it gets closer to the rotational axis of the magnetic recording disk, since the airflow of a smaller flow rate is generated along the surface of the magnetic recoding disk at an inward position closer to the rotational axis as compared with that at an outward position closer to the outer periphery. The upstream or leading end of the head slider is more distanced apart from the magnetic recording disk at the outward position. In particular, the head slider including the front rail extending in the lateral direction tends to suffer from decrease in the negative pressure as it gets closer to the rotational axis. This involuntarily induces variation in the flying height of the head slider.
It is accordingly an object of the present invention to provide a flying head slider capable of avoiding any collision upon dropping off a ramp without losing the stability of the attitude during flight.
According to a first aspect of the present invention, there is provided a flying head slider comprising: a slider body; a generally flat bottom surface defined on the slider body; a front rail standing on the bottom surface at an upstream position; a front air bearing surface defined on the front rail; a rear rail standing on the bottom surface at a downstream position; and a rear air bearing surface defined on the rear rail. The upstream end of the bottom surface is defined along a first datum line extending in the lateral direction of the slider body, while the upstream end of the front air bearing surface is defined along a second datum line intersecting the first datum line at a predetermined inclined angle.
The flying head slider is designed to receive an airflow at the front and rear air bearing surfaces so as to fly. If the lift generated on the front air bearing surface gets increased in response to an increase in the flow rate of the airflow, the attitude of the slider body varies during flight of the flying head slider, for example. However, a decreased incidence angle of the airflow in response to the increase in the flow rate of the airflow enables a stable attitude of the slider body during flight of the flying head slider. The inclined angle defined between the first and second datum lines serves to intentionally induce the decrease in the incidence angle of the airflow in the flying head slider of the first aspect.
In particular, it is preferable that the front rail is designed to define a front surface standing on the bottom surface at a position distanced downstream from the upstream end of the bottom surface. The front surface of this type allows generation of a relatively larger lift on the flying head slider at the moment when the flying head slider falls and starts receiving the airflow. Consequently, the amount of falling of the flying head slider can be minimized. Moreover, even when the slider body takes an inclined attitude keeping the upstream or leading end lower during the falling of the flying head slider, the front surface also serves to straighten the inclined attitude of the slider body. The slider body is forced to take the normal attitude in which the slider body receives an enough lift resulting from the airflow. When the flying head slider of this type is employed in a recording disk drive, the flying head slider is reliably prevented from colliding against a recording medium or disk at the moment when the flying head slider is loaded.
According to a second aspect of the present invention, there is provided a flying head slider comprising: a slider body; a generally flat bottom surface defined on the slider body; a front rail standing on the bottom surface at an upstream position so as to extend in a lateral direction of the slider body; a front air bearing surface defined on a top surface of the front rail; a rear rail standing on the bottom surface at a downstream position; a rear air bearing surface defined on the rear rail; a front surface defined on the front rail so as to stand on the bottom surface at a position distanced downstream from an upstream end of the bottom surface; a step connected to an upstream end of the front air bearing surface on the front rail; a first columnar piece standing on the bottom surface along the front surface; and a second columnar piece standing on the bottom surface along the front surface so as to define an air clogging dished space adjacent the front surface in cooperation with the first columnar piece.
The front surface allows generation of a relatively larger lift on the flying head slider at the moment when the flying head slider falls and starts receiving the airflow in the aforementioned manner. Consequently, the amount of falling of the flying head slider can be minimized. Moreover, the air clogging dished space enables a stable attitude of the slider body during flight of the flying head slider irrespective of any increase in the flow rate of the airflow.